Method for reducing impurities in trifluoroiodomethane process

Abstract

The present disclosure provides a process for producing trifluoroiodomethane (CF 3 I), with a low concentration of methyl propane. Specifically, the present disclosure provides a process for producing trifluoroiodomethane (CF 3 I) with an amount of methyl propane of 100 ppm or less.

What is claimed is: 
     
         1 . A process for producing trifluoroiodomethane (CF 3 I) with a low concentration of methyl propane, the process comprising:
 providing a first reactant stream comprising hydrogen iodide (HI);   reacting the first reactant stream with a second reactant stream comprising trifluoroacetyl chloride (TFAC) to produce an intermediate product stream comprising trifluoroacetyl iodide (TFAI);   purifying the intermediate product stream to remove methyl propane; and   reacting the purified intermediate product stream to produce a final product stream comprising trifluoroiodomethane (CF 3 I).   
     
     
         2 . The process of  claim 1 , wherein the amount of iodomethane in the hydrogen iodide (HI) is less than 250 ppm. 
     
     
         3 . The process of  claim 1 , wherein the amount of iodopropane in the hydrogen iodide (HI) is less than 250 ppm. 
     
     
         4 . The process of  claim 1 , wherein the trifluoroacetyl iodide (TFAI) is purified by distillation. 
     
     
         5 . The process of  claim 1 , wherein the trifluoroacetyl iodide (TFAI) is purified by solvent extraction. 
     
     
         6 . The process of  claim 5 , wherein the solvent used for the solvent extraction is selected from the group consisting of hydrocarbons and chlorinated compounds. 
     
     
         7 . The process of  claim 5 , wherein the solvent used for the solvent extraction is regenerated by distillation. 
     
     
         8 . The process of  claim 1 , wherein the trifluoroacetyl iodide (TFAI) is purified with an adsorbent. 
     
     
         9 . The process of  claim 8 , wherein the adsorbent is selected from the group consisting of molecular sieves, carbon, carbon molecular sieves, alumina, and zeolites. 
     
     
         10 . The process of  claim 1 , wherein the concentration of trifluoroacetyl iodide (TFAI) in the purified intermediate product stream is greater than about 99 wt. % based on the total weight of the composition. 
     
     
         11 . The process of  claim 1 , wherein the amount of methyl propane in the in purified intermediate product stream is about 50 ppm or less. 
     
     
         12 . The process of  claim 1 , further comprising purifying the final product stream comprising trifluoroiodomethane (CF 3 I) by distillation. 
     
     
         13 . The process of  claim 1 , further comprising purifying the final product stream comprising trifluoroiodomethane (CF 3 I) with an adsorbent. 
     
     
         14 . The process of  claim 13 , wherein the adsorbent is selected from the group consisting of molecular sieves, carbon, carbon molecular sieves, alumina, and zeolites. 
     
     
         15 . The process of  claim 1 , wherein the amount of methyl propane in the trifluoroiodomethane (CF 3 I) product is about 70 ppm or less. 
     
     
         16 . A composition comprising:
 at least 99 wt. % of trifluoroiodomethane   less than 500 ppm chlorotrifluoroethane;   less than 500 ppm hexafluoroethane;   less than 500 ppm trifluoromethane;   less than 100 ppm carbon monoxide;   less than 100 ppm carbon methyl propane and   less than 1 ppm hydrogen chloride.   
     
     
         17 . The composition of  claim 16 , further comprising:
 from 1 ppm to 500 ppm in total of compounds selected from the group consisting of trifluoroacetyl fluoride, hexafluoropropanone, trifluoroacetaldehyde, and trifluoroacetyl chloride.   
     
     
         18 . The composition of  claim 16 , wherein the amount of methyl propane less than 70 ppm. 
     
     
         19 . A process for producing trifluoroacetyl iodide (TFAI) with a low concentration of methyl propane, the process comprising:
 providing a first reactant stream comprising a purified stream of hydrogen iodide (HI);   reacting the first reactant stream with a second reactant stream comprising trifluoroacetyl chloride (TFAC) to produce a final product stream comprising trifluoroacetyl iodide (TFAI).   
     
     
         20 . The process of  claim 19 , wherein the amount of iodomethane in the hydrogen iodide (HI) is less than 250 ppm.